Rotary control knob for an appliance



FIG. 1 is a upper left perspective view of a rotary control knob for an appliance, showing my new design;

FIG. 2 is an enlarged, upper right perspective view of the rotary control knob of the invention;

FIG. 3 is a side elevational view of the rotary control knob of the invention, the remaining sides being identical; and,

FIG. 4 is a top plan view of the rotary control knob of the invention.

The bottom of the control knob does not form part of the invention and is therefore not depicted.

The broken line showing in FIG. 1 is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a rotary control knob for an appliance, as shown and described. 